Structural and optical properties of Si₂Te₃nanowires

Si₂Te₃ has recently attracted attention as a new class of layered 2D materials, which promise useful applications in thermal electrics and chemical sensing. Here, we report a study of the structural and optical properties of Si₂Te₃nanowires (NW) at various conditions. Single-crystalline Si₂Te₃NWs were synthesized by using gold nanoparticles as catalysts through the vapor-liquid-solid (VLS) mechanism. It was observed that these NWs prefer to grow along the [0001] direction, which is perpendicular to the 2D layers. Spectral and temporal characteristics of photoexcited carriers in these Si₂Te₃ NWs were investigated at various temperatures and excitation powers. Photoluminescence spectrum of Si₂Te₃ NWs was dominated by defect and surface states related emissions at both low and room temperatures. Consequently, the decay time of photoexcited carries strongly depends on the measurements at different temperatures and excitation powers. Our results quantitatively elucidate decay mechanisms that are important towards understanding and controlling of the electronic states in Si₂Te₃nanostructures for optoelectronic applications.